Symposium review: Integration of postweaning nutrient requirements and supply with composition of growth and mammary development in modern dairy heifers.

To optimize first lactation and lifetime milk yield, growth benchmarks were established to help meet the appropriate growth objectives of breeding weight and age at an economically viable time and to achieve the optimum body size and composition at first calving. These guidelines provide a framework that helps to minimize overfeeding and, thus, potential overconditioning of heifers, which can lead to postpartum metabolic issues and reduced milk yield. Concerns still exist that mammary development is impaired when body weight gain exceeds a certain threshold, which would negatively affects milk yield.

Preweaning nutrient supply alters mammary gland transcriptome expression relating to morphology, lipid accumulation, DNA synthesis, and RNA expression in Holstein heifer calves.

The objective of this study was to analyze the mammary gland transcriptome to determine how preweaning nutrient supply alters the molecular mechanisms that regulate preweaning mammary development. Holstein heifers were fed via milk replacer (MR) either an elevated level of nutrient intake (ELE; on average, 5.9 ± 0.

Nutrient supply alters transcriptome regulation in adipose tissue of pre-weaning Holstein calves.

Performance of dairy cows can be influenced by early life nutrient supply. Adipose tissue is diet sensitive and an important component in that process as it is involved in the regulation of energetic, reproductive and immunological functions. However, it is not clear how early life nutrition alters the molecular regulation of adipose tissue in calves and potentially adult individuals.

Abrupt weaning reduces postweaning growth and is associated with alterations in gastrointestinal markers of development in dairy calves fed an elevated plane of nutrition during the preweaning period.

The benefits of feeding elevated quantities of milk to dairy calves have been well established. However, there is a reluctance to adopt this method of feeding in commercial dairy production because of concerns around growth, health, and ruminal development during weaning. The objective of this study was to characterize the effect of an abrupt (0 d step-down) or gradual (12 d step-down) feeding scheme when calves are fed an elevated plane of nutrition (offered 1.

Effects of preweaning nutrient intake in the developing mammary parenchymal tissue.

Historically, mammary gland growth has been considered isometric the first 2 mo of life and then allometric until peripuberty. However, recent work indicated that the mammary gland might be responsive to nutrient intake preweaning. The objectives of this study were to describe the effects of nutrient intake preweaning on mammary gland development and to investigate cell specific proliferation during this phase of development.